DE102005018922A1 - Polycation-surface-treated water-absorbing polymer structure - Google Patents

Abstract

The present invention relates to water-absorbing polymer structures, whose surface has been brought into contact with a compound comprising a polycation and at least one anion. The invention further relates to a process for treating the surface of water-absorbing polymer structures, the surface-treated water-absorbing polymer structures obtainable by this process, a composite comprising a surface-treated, water-absorbing polymer structure as well as a substrate, a process for production of a composite, the composite obtainable by this process, chemical products such as foams, formed bodies, and fibers comprising surface-treated water-absorbing polymer structures or a composite, the use of surface-treated, water-absorbing polymer structures or of a composite in chemical products as well as the use of compounds comprising a polycation with a given structure for the treatment of the surface of water-absorbing polymer structures.

Description

The The present invention relates to a water-absorbing polymer structure, a method of treating the surface of water-absorbing polymer structures, those obtainable by this method surface-treated, water-absorbing polymer structure comprising a composite water-absorbing polymer structure and a substrate, a method for producing a composite obtainable by this process Composite comprising chemical products such as foams, shaped bodies and fibers water-absorbing polymer structures or a composite, the use water-absorbing polymer structure or a composite in chemical Products as well as the use of compounds comprising a polycation having a specific structure for treating the surface of water-absorbing Polymer structure.

superabsorbent are water-insoluble, crosslinked polymers that are capable of swelling and forming of hydrogels great Amounts of aqueous Liquids, especially body fluids, preferably urine or blood, and take under a certain Withhold pressure. By these characteristic properties these polymers find mainly Application in the incorporation in sanitary articles, such as Baby diapers, incontinence products or sanitary napkins.

The production of the superabsorbents is generally carried out by the radical polymerization of acid group-carrying monomers in the presence of crosslinking agents. By selecting the monomer composition, the crosslinker and the polymerization conditions and the processing conditions for the hydrogel obtained after the polymerization, polymers having different absorber properties can be prepared. Further possibilities are offered by the preparation of graft polymers, for example using chemically modified starch, cellulose and polyvinyl alcohol according to DE-OS 26 12 846 and the aftertreatment of the hydrogels or the powdered polymer particles obtained after drying of the hydrogels by postcrosslinking the surfaces of the polymer particles, for example DE 40 20 780 C1 , By the post-crosslinking of the surface of the water-absorbing polymer particles, in particular, the absorption capacity of the polymer particles is increased under the action of pressures.

EP 0 248 963 A2 proposes to coat the water-absorbing polymer particles with polyquaternary amines in order to improve the absorption capacity and the retention of water. The disadvantage of in EP 0 248 973 A2 described water-absorbing polymer particles, however, is that although they show improved absorption capacity and improved retention due to the coating with the quaternary amines used there, absorbent structures which include these polymers in high concentrations, but characterized by an unsatisfactory absorption behavior. This unsatisfactory absorption behavior is manifested in particular by the so-called "gel-blocking effect." This "gel-blocking" effect is understood to mean that, in absorbent structures, the diffusion of liquids into the structure is due to the limited permeability of the absorbent structure is less than the rate at which the liquid enters the absorbent structure so that, for example, when the absorbent structure is a diaper, liquid leakage may occur.

Of the The present invention was therefore the object of the to overcome disadvantages resulting from the prior art.

Especially The object of the present invention was to provide superabsorbents and absorbent structures containing these superabsorbents in provide high levels, in addition to excellent absorption and retention properties thereby also particularly advantageous permeability Marked are.

Farther The object of the present invention was to provide methods with the superabsorbent and a composite containing these superabsorbents can be made with the advantages mentioned above.

A contribution to the achievement of the abovementioned objects is provided by a water-absorbing polymer structure whose surface has been brought into contact with a compound comprising a polycation and at least one anion and which preferably has a composition according to ERT 442.2-02 (ERT = Edana Dedicated Test Method) has a specific absorption under a pressure of 50 g / cm ² of at least 16 g / g, more preferably of at least 18 g / g and most preferably of at least 20 g / g, preferably absorbing under a pressure of 50 g / cm ² of 100 g / g, more preferably of 50 g / g and more preferably of 40 g / g is not exceeded (in the case of particles in each case determined for the entire particle fraction).

a Contribution to the solution The above-mentioned objects also provide a water-absorbing polymer structure, its surface with a compound comprising a polycation and at least one Anion has been brought into contact, wherein the compound comprising a polycation and at least one anion a weight average molecular weight of more than 3,000 g / mol, preferably more than 4,000 g / mol, even more preferably more than 5,000 g / mol, moreover more preferred more than 7,000 g / mol and most preferably more than 10,000 g / mol preferably having a weight average molecular weight of 100,000,000 g / mol, more preferably 10,000,000 g / mol not exceeded becomes.

In a preferred embodiment the water-absorbing invention Polymer structures are these surface postcrosslinked. surface post Polymeric structures are characterized by having an interior area and an outdoor area surrounding the interior, wherein the outdoor area a higher Vernetzungsgad has as the interior.

According to the invention preferred Polymeric structures are fibers, foams or particles, with fibers and particles being preferred and particles are particularly preferred.

According to the invention preferred Polymer fibers are sized to be in or as yarns for textiles and can also be incorporated directly into textiles. It is preferred according to the invention, that the polymer fibers have a length in the range of 1 to 500 mm, preferably 2 to 500 mm and especially preferably 5 to 100 mm and a diameter in the range of 1 to 200 denier, preferably 3 to 100 denier and more preferably 5 own up to 60 deniers.

According to the invention preferred Polymer particles are sized to have an average particle size according to ERT 420.2-02 in the range of 10 to 3000 μm, preferably 20 to 2000 microns and more preferably 150 to 850 microns. It is in particular preferred that the proportion of the polymer particles having a particle size in one Range of 300 to 600 microns at least 30% by weight, more preferably at least 40% by weight, about that more preferably at least 50% by weight, and most preferably at least 75 wt .-%, based on the total weight of the postcrosslinked, water-absorbing Polymer particles, amounts. According to one another embodiment the water-absorbing invention Polymer structure is the proportion of polymer particles having a particle size in one Range from 150 to 850 μm at least 50% by weight, more preferably at least 75% by weight, about that In addition, at least 90% by weight, and most preferably at least, is preferred 95 wt .-%, based on the total weight of the postcrosslinked, water-absorbing Polymer particles.

• (α1) 20–99,999 Gew.-%, bevorzugt 55–98,99 Gew.-% und besonders bevorzugt 70–98,79 Gew.-% polymerisierten, ethylenisch ungesättigten, säuregruppentragenden Monomeren oder deren Salze oder polymerisierten, ethylenisch ungesättigten, einen protonierten oder quarternierten Stickstoff beinhaltenden Monomeren, oder deren Mischungen, wobei mindestens ethylenisch ungesättigte, säuregruppenhaltige Monomere, vorzugsweise Acrylsäure, beinhaltende Mischungen besonders bevorzugt sind,
• (α2) 0–80 Gew.-%, vorzugsweise 0–44,99 Gew.-% und besonders bevorzugt 0,1-44,89 Gew.-% polymerisierten, monoethylenisch ungesättigten, mit (α1) copolymerisierbaren Monomeren,
• (α3) 0,001–5 Gew.-%, vorzugsweise 0,01–3 Gew.-% und besonders bevorzugt 0,01–2,5 Gew.-% eines oder mehrerer Vernetzer,
• (α4) 0,001–10 Gew.-%, vorzugsweise 0,01–7,5 Gew.-% und am meisten bevorzugt 0,5–5 Gew.-% der Verbindung umfassend mindestens ein Anion und ein Polykation,
• (α5) 0–30 Gew.-%, vorzugsweise 0–5 Gew.-% und besonders bevorzugt 0,1–5 Gew.-% eines wasserlöslichen Polymeren,
• (α6) 0–20 Gew.-%, vorzugsweise 2,5–15 Gew.-% und besonders bevorzugt 5–10 Gew.-% Wasser, sowie
• (α7) 0–20 Gew.-%, vorzugsweise 0–10 Gew.-% und besonders bevorzugt 0,1–8 Gew.-% eines oder mehrerer Hilfsmittel, wobei die Summe der Gewichtsmengen (α1) bis (α7) 100 Gew.-% beträgt.

In a preferred embodiment of the water-absorbing polymer structures according to the invention, these are based on

• (α1) 20-99.999 wt .-%, preferably 55-98.99 wt .-% and particularly preferably 70-98.79 wt .-% polymerized, ethylenically unsaturated, acid group-carrying monomers or their salts or polymerized, ethylenically unsaturated, one protonated or quaternized nitrogen-containing monomers, or mixtures thereof, wherein at least ethylenically unsaturated, acid group-containing monomers, preferably acrylic acid-containing mixtures are particularly preferred,
• (α2) 0-80 wt .-%, preferably 0-44.99 wt .-% and particularly preferably 0.1-44.89 wt .-% polymerized, monoethylenically unsaturated, with (α1) copolymerizable monomers,
• (α3) 0.001-5 wt .-%, preferably 0.01-3 wt .-% and particularly preferably 0.01-2.5 wt .-% of one or more crosslinkers,
• (α4) 0.001-10% by weight, preferably 0.01-7.5% by weight and most preferably 0.5-5% by weight of the compound comprising at least one anion and one polycation,
• (α5) 0-30 wt .-%, preferably 0-5 wt .-% and particularly preferably 0.1-5 wt .-% of a water-soluble polymer,
• (α6) 0-20 wt .-%, preferably 2.5-15 wt .-% and particularly preferably 5-10 wt .-% water, and
• (α7) 0-20 wt .-%, preferably 0-10 wt .-% and particularly preferably 0.1-8 wt .-% of one or more auxiliaries, wherein the sum of the amounts by weight (α1) to (α7) 100 wt .-% is.

The monoethylenically unsaturated acid group-containing monomers (α1) may be partially or fully constantly, preferably partially neutralized. The monoethylenically unsaturated monomers containing acid groups are preferably neutralized to at least 25 mol%, particularly preferably to at least 50 mol% and moreover preferably to 50-80 mol%. In this context is on DE 195 29 348 A1 The disclosure of which is hereby incorporated by reference. The neutralization can be done partially or completely even after the polymerization. Furthermore, the neutralization can be carried out with alkali metal hydroxides, alkaline earth metal hydroxides, ammonia and carbonates and bicarbonates. In addition, every other base is conceivable, which forms a water-soluble salt with the acid. Also a mixed neutralization with different bases is conceivable. Preference is given to neutralization with ammonia and alkali metal hydroxides, particularly preferably with sodium hydroxide and with ammonia.

Further can for a polymer, the free acid groups predominate, so that this polymer has a pH in the acidic range having. This acidic water-absorbing polymer can be replaced by a polymer with free basic groups, preferably amine groups, by comparison to which the acidic polymer is basic, at least partially neutralized become. These polymers are referred to in the literature as "Mixed-Bed Ion-Exchange Absorbent Polymers "(MBIEA polymers) and are disclosed inter alia in WO 99/34843 A1. The revelation WO 99/34843 A1 is hereby incorporated by reference and is thus considered part of the revelation. In general, MBIEA polymers provide a composition comprising, on the one hand, basic polymers which are used in are able to exchange anions, and on the other hand a comparison to the basic polymer acidic polymer that is capable of cations exchange. The basic polymer has basic groups and is typically due to the polymerization of monomers obtained that carry basic groups or groups that are basic Groups can be converted. These monomers are, above all, those the primary, secondary or tertiary Amines or the corresponding phosphines or at least two of the have the above functional groups. To this group of Monomers belong especially ethyleneamine, allylamine, diallylamine, 4-aminobutene, Alkyloxycycline, vinylformamide, 5-aminopentene, carbodiimide, formaldacin, Melamine and the like, as well as their secondary or tertiary amine derivatives.

preferred ethylenically unsaturated, containing acid groups Monomers (α1) are preferably those compounds described in WO 2004/037903 A2, which is hereby incorporated by reference and thus as part of the Revelation applies as ethylenically unsaturated, acid group-containing monomers called (α1) become. Particularly preferred ethylenically unsaturated, acid group-containing monomers (α1) acrylic acid and methacrylic acid, being acrylic acid most preferred.

According to one embodiment the method according to the invention Water-absorbing polymer structures are used in which the monoethylenically unsaturated, with (α1) copolymerizable monomers (α2) Acrylamides, methacrylamides or vinylamides are.

preferred (Meth) acrylamides are alkyl-substituted in addition to acrylamide and methacrylamide (Meth) acrylamides or aminoalkyl-substituted derivatives of (meth) acrylamide, such as N-methylol (meth) acrylamide, N, N-dimethylamino (meth) acrylamide, Dimethyl (meth) acrylamide or diethyl (meth) acrylamide. Possible vinylamides are for example N-vinylamides, N-vinylformamides, N-vinylacetamides, N-vinyl-N-methylacetamides, N-vinyl-N-methylformamide, vinylpyrrolidone. Among these monomers especially preferred is acrylamide.

According to one another embodiment the method according to the invention Water-absorbing polymer structures are used in which the monoethylenically unsaturated, with (α1) copolymerizable monomers (α2) water-soluble Are monomers. In this connection, in particular alkoxypolyalkylene oxide (meth) acrylates such as methoxypolyethylene glycol (meth) acrylates preferred.

Of Further, as monoethylenically unsaturated, with (α1) copolymerizable Monomers (α2) water-dispersible monomers are preferred. As dispersible in water Monomers are acrylic esters and methacrylates, such as methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate or butyl (meth) acrylate.

The monoethylenically unsaturated, with (α1) copolymerizable monomers (α2) further include methyl polyethylene glycol allyl ether, vinyl acetate, Styrene and isobutylene.

Crosslinkers (α3) used are preferably those compounds which are mentioned in WO 2004/037903 A2 as crosslinking agents (α3). Among these crosslinkers, water-soluble crosslinkers are particularly preferred. Most preferred are N, N'-methylenebisacrylamide, polyethylene glycol di (meth) acrylates, triallylmethylammonium chloride, tetraallylammonium chloride and 9 moles of ethylene oxide per Allylnonaethylenglykolacrylat made of acrylic acid especially preferred.

Struktur I aufweist, in der
R¹ und R² gleich oder verschieden sein können und ein Kohlenwasserstoffrest mit 1 bis 10 Kohlenstoffatomen, vorzugsweise 1 bis 7 Kohlenstoffatomen, besonders bevorzugt 1 bis 4 Kohlenstoffatomen, darüber hinaus bevorzugt 1 bis 2 Kohlenstoffatomen und am meisten bevorzugt eine Methylgruppe darstellen und
n einen Wert von mindestens 25, vorzugsweise mindestens 31, noch mehr bevorzugt mindestens 100, darüber hinaus bevorzugt mindestens 1.000, darüber hinaus noch mehr bevorzugt mindestens 2.500 und am meisten bevorzugt mindestens 5.000 hat.Preferred compounds (α4) comprising at least one anion and one polycation are compounds in which the polycation has the structure I

Structure I has, in the
R ¹ and R ^{2 may be the} same or different and represent a hydrocarbon radical having 1 to 10 carbon atoms, preferably 1 to 7 carbon atoms, more preferably 1 to 4 carbon atoms, more preferably 1 to 2 carbon atoms, and most preferably a methyl group, and
n has a value of at least 25, preferably at least 31, even more preferably at least 100, moreover preferably at least 1,000, moreover still more preferably at least 2,500 and most preferably at least 5,000.

Especially Preferred polycations of structure I are polydiallyldimethylamines. Preferred anions are the chloride ion, the bromide ion, the iodide ion, sulfide ion, sulfate ion, sulfate ion, nitrate ion, the nitrite ion, the acetate ion, the lactate ion, the carbonate ion, the bicarbonate ion, the phosphate ion, the phosphite ion and the hydroxide ion. In addition to these mono- or divalent anions can the compound also includes polyvalent anions. A special preferred compound containing at least one anion and one polycation is a polymer of diallyldimethylammonium chloride with a value of n of at least 25, preferably at least 31, moreover preferably at least 100, above more preferably at least 1,000, more preferably at least 2,500 and most preferably at least 5,000.

When water-soluble Polymers (α5) can water-soluble in the polymer structures Polymers, such as partially or fully saponified polyvinyl alcohol, polyvinylpyrrolidone, Strength or starch derivatives, Polyglycols or polyacrylic acid contained, preferably copolymerized. The molecular weight These polymers are not critical as long as they are water soluble. Preferred water-soluble Polymers are starch or starch derivatives or Polyvinyl alcohol. The water-soluble Polymers, preferably synthetic ones such as polyvinyl alcohol, may also be used as a grafting base for serve the monomers to be polymerized.

When Aids (α6) are preferably settling agents, odor binders, surface-active Agents or antioxidants as well as those additives that are used to manufacture the polymer structures were used (initiators, etc.) in the polymer structures contain.

In a particular embodiment the polymer structures of the invention These are based to at least 50 wt .-%, preferably at least 70% by weight and above more preferably at least 90% by weight on carboxylate-bearing Monomers. It is still according to the invention preferred that the component (α1) at least 50 wt .-%, preferably at least 70 wt .-% of acrylic acid which is preferably at least 20 mol%, more preferably to at least 50 mol% and above Moreover, it is preferably neutralized in a range of 60 to 85% by mole is.

Farther It should be noted that the compound comprising at least one Anion and the polycation not in the entire surface area must be immobilized. However, it is preferred according to the invention that at least 5%, preferably at least 10%, still more preferably at least 20% and most preferably at least 30% of the outer surface of these Compound is immobilized.

• (β1) kein Verbacken nach drei Stunden, vorzugsweise nach 6 Stunden und besonders bevorzugt nach 12 Stunden in dem in der WO 00/10619 A1 beschriebenen „anti-caking"-Test;
• (β2) bei einem gemäß ERT 441.2–02 bestimmten CRC-Wert (CRC = Centrifugation Retention Capacity; im Falle von Partikeln jeweils bestimmt für die gesamte Partikelfraktion) von weniger als 26 g/g einen gemäß der hierin beschriebenen Testmethode bestimmten SFC-Wert (SFC = Saline Flow Conductivity) von mindestens 80 × 10^–7 cm³ s g^–1, vorzugsweise von mindestens 90 × 10^–7 cm³ s g^–1 und am meisten bevorzugt von mindestens 100 × 10^–7 cm³ s g^–1;
• (β3) bei einem gemäß ERT 441.2–02 bestimmten CRC-Wert im Bereich von 26 bis < 27 g/g einen gemäß der hierin beschriebenen Testmethode bestimmten SFC-Wert von mindestens 70 × 10^–7 cm³ s g^–1, vorzugsweise von mindestens 80 × 10^–7 cm³ s g^–1 und am meisten bevorzugt von mindestens 90 × 10^–7 cm³ s g^–1;
• (β4) bei einem gemäß ERT 441.2–02 bestimmten CRC-Wert im Bereich von 27 bis < 28 g/g einen gemäß der hierin beschriebenen Testmethode bestimmten SFC-Wert von mindestens 60 × 10^–7 cm³ s g^–1, vorzugsweise von mindestens 70 × 10^–7 cm³ s g^–1 und am meisten bevorzugt von mindestens 80 × 10^–7 cm³ s g^–1;
• (β5) bei einem gemäß ERT 441.2–02 bestimmten CRC-Wert im Bereich von 28 bis < 29 g/g einen gemäß der hierin beschriebenen Testmethode bestimmten SFC-Wert von mindestens 45 × 10^–7 cm³ s g^–1, vorzugsweise von mindestens 55 × 10^–7 cm³ s g^–1 und am meisten bevorzugt von mindestens 65 × 10^–7 cm³ s g^–1;
• (β6) bei einem gemäß ERT 441.2–02 bestimmten CRC-Wert im Bereich von 29 bis < 30 g/g einen gemäß der hierin beschriebenen Testmethode bestimmten SFC-Wert von mindestens 30 × 10^–7 cm³ s g^–1, vorzugsweise von mindestens 40 × 10^–7 cm³ s g^–1 und am meisten bevorzugt von mindestens 50 × 10^–7 cm³ s g^–1;
• (β7) bei einem gemäß ERT 441.2–02 bestimmten CRC-Wert im Bereich von 30 bis < 31 g/g einen gemäß der hierin beschriebenen Testmethode bestimmten SFC-Wert von mindestens 20 × 10^–7 cm³ s g^–1, vorzugsweise von mindestens 30 × 10^–7 cm³ s g^–1 und am meisten bevorzugt von mindestens 40 × 10^–7 cm³ s g^–1;
• (β8) bei einem gemäß ERT 441.2–02 bestimmten CRC-Wert von mindestens 31 g/g einen gemäß der hierin beschriebenen Testmethode bestimmten SFC-Wert von mindestens 10 × 10^–7 cm³ s g^–1, vorzugsweise von mindestens 20 × 10^–7 cm³ s g^–1 und am meisten bevorzugt von mindestens 30 × 10^–7 cm³ s g^–1;
• (β9) einen gemäß der hierin beschriebenen Testmethode bestimmten Wicking-Index nach einer Minute von mindestens 7,5 cm, vorzugsweise mindestens 8,5 cm und am meisten bevorzugt mindestens 10,0 cm;
• (β10) einen Neutralisationsgrad von höchstens 75 Mol-%, vorzugsweise höchstens 70 Mol % und am meisten bevorzugt höchstens 65 Mol-%.

Furthermore, the polymer structures according to the invention are preferably characterized by at least one of the following properties:

• (β1) no caking after three hours, preferably after 6 hours and more preferably after 12 hours in the "anti-caking" test described in WO 00/10619 A1;
• (β2) at a CRC value (CRC) determined in accordance with ERT 441.2-02 of less than 26 g / g in the case of particles of less than 26 g / g, an SFC value determined according to the test method described herein ( SFC = Saline Flow Conductivity) of at least 80 × 10 ^-7 cm ³ sg ^-1 , preferably of at least 90 × 10 ^-7 cm ³ sg ^-1 and most preferably of at least 100 × 10 ^-7 cm ³ sg ^-1 ;
• (β3) at a CRC value in accordance with ERT 441.2-02 in the range of 26 to <27 g / g, an SFC value of at least 70 x 10 ^-7 cm ³ sg ^-1 determined according to the test method described herein, preferably at least 80 x 10 ^-7 cm ³ sg ^-1 and most preferably at least 90 x 10 ^-7 cm ³ sg ^-1 ;
• (β4) at a CRC value in the range of 27 to <28 g / g, determined according to ERT 441.2-02, an SFC value of at least 60 x 10 ^-7 cm ³ sg ^-1 , preferably at least determined according to the test method described herein 70 x 10 ^-7 cm ³ sg ^-1 and most preferably at least 80 x 10 ^-7 cm ³ sg ^-1 ;
• (β5) at a CRC value in accordance with ERT 441.2-02 ranging from 28 to <29 g / g, an SFC value of at least 45 x 10 ^-7 cm ³ sg ^-1 determined according to the test method described herein, preferably at least 55 x 10 ^-7 cm ³ sg ^-1 and most preferably at least 65 x 10 ^-7 cm ³ sg ^-1 ;
• (β6) at a CRC value in the range of 29 to <30 g / g, determined according to ERT 441.2-02, an SFC value of at least 30 × 10 ^-7 cm ³ sg ^-1 , preferably at least determined according to the test method described herein 40 x 10 ^-7 cm ³ sg ^-1 and most preferably at least 50 x 10 ^-7 cm ³ sg ^-1 ;
• (β7) at a CRC value in the range of 30 to <31 g / g, determined according to ERT 441.2-02, an SFC value of at least 20 × 10 ^-7 cm ³ sg ^-1 , preferably at least determined according to the test method described herein 30 x 10 ^-7 cm ³ sg ^-1 and most preferably at least 40 x 10 ^-7 cm ³ sg ^-1 ;
• (β8) at a CRC value of at least 31 g / g determined according to ERT 441.2-02, an SFC value of at least 10 × 10 ^-7 cm ³ sg ^-1 , preferably of at least 20 × 10 ^, determined according to the test method described herein ^{. 7} cm ³ sg ^-1 and most preferably at least 30 × 10 ^-7 cm ³ sg ^-1 ;
• (β9) a wicking index determined according to the test method described herein after one minute of at least 7.5 cm, preferably at least 8.5 cm, and most preferably at least 10.0 cm;
• (β10) a degree of neutralization of at most 75 mol%, preferably at most 70 mol%, and most preferably at most 65 mol%.

Farther preferred embodiments the polymer structures of the invention have every conceivable combination of the above features (β1) to (β10), the embodiments of the following combinations of features are preferred: (β1), (β2), (β3), (β4), (β5), (β6), (β7), (β8), (β9), (β10), (β1) ( β9), (β2) (β3) (β4) (β5) (β6) (β7) (β8) (β9) and (β1) (β2) (β3) (β4) (β5) (β6) (β7) ( β8) (β9) (β10), where (β9), (β1) (β9) and (β1) (β2) (β3) (β4) (β5) (β6) (β7) (β8) (β9) (β10) preferred property combinations are.

• i) Bereitstellen eines unbehandelten, wasserabsorbierenden Polymergebildes,
• ii) in Kontakt bringen des unbehandelten wasserabsorbierenden Polymergebilde mit einer mindestens ein Anionen und ein Polykation umfassenden Verbindung,
• iii) gegebenenfalls Nachvernetzung des wasserabsorbierenden Polymergebildes,

wobei der Verfahrensschritt iii) vor, während oder nach dem Verfahrensschritt ii) durchgeführt werden kann.A contribution to the solution of the abovementioned objects is also provided by a process for the treatment of the surface of water-absorbing polymer structures, comprising the process steps:

• i) providing an untreated, water-absorbing polymer structure,
• ii) contacting the untreated water-absorbing polymer structure with a compound comprising at least one anion and one polycation,
• iii) optionally postcrosslinking of the water-absorbing polymer structure,

wherein the method step iii) before, during or after the method step ii) can be carried out.

"Un treated" in the sense of the present Invention means that the water-absorbing polymer structures not yet having the compound comprising at least one anion and brought a polycation of the structure I in contact and also not surface postcrosslinked have been. The term "untreated", however, concludes not that the water-absorbing polymer structures by means of other surface modification measures, such as coating with silica or silica for Purposes of increase the permeability the polymer structure in the swollen state or the surface treatment with Aluminum salts can be modified.

• a) radikalische Polymerisation säuregruppen-tragender, ethylenisch ungesättigter, gegebenenfalls teilneutralisierter Monomere in Gegenwart eines Vernetzers unter Bildung eines Hydrogels;
• b) gegebenenfalls Zerkleinern des Hydrogels;
• c) zumindest teilweises Trocknen des gegebenenfalls zerkleinerten Hydrogels unter Erhalt wasserabsorbierender Polymergebilde;
• d) gegebenenfalls Zermahlen des so erhaltenen absorbierenden Polymergebildes und absieben auf eine gewünschte Partikelgrößenfraktion;
• e) gegebenenfalls weitere Oberflächenmodifizierungen der so erhalten wasserabsorbierenden Polymergebilde.

As untreated, water-absorbing polymer structures, in process step i) it is preferable to provide polymers which have been obtained by a process comprising the process steps:

• a) free radical polymerization of acid group-carrying, ethylenically unsaturated, optionally partially neutralized monomers in the presence of a crosslinker to form a hydrogel;
• b) optionally comminuting the hydrogel;
• c) at least partial drying of the optionally comminuted hydrogel to obtain water-absorbing polymer structures;
• d) optionally grinding the thus obtained absorbent polymer structure and sieving on a desired particle size fraction;
• e) optionally further surface modifications of the resulting water-absorbing polymer structures.

• (α1) die ethylenisch ungesättigten, säuregruppen-tragenden Monomeren oder deren Salze, wobei Acrylsäure als säuregruppentragendes Monomer besonders bevorzugt ist,
• (α2) gegebenenfalls monoethylenisch ungesättigte, mit (α1) copolymerisierbare Monomere,
• (α3) den Vernetzer,
• (α5) gegebenenfalls ein wasserlösliches Polymer, sowie
• (α7) gegebenenfalls einen oder mehrere Hilfsmittel.

The radical polymerization taking place in process step a) is preferably carried out in aqueous solution, this aqueous solution preferably being used in addition to water as solvent

• (α1) the ethylenically unsaturated acid group-carrying monomers or their salts, acrylic acid being particularly preferred as the acid group-carrying monomer,
• (α2) optionally monoethylenically unsaturated monomers copolymerizable with (α1),
• (α3) the crosslinker,
• (α5) optionally a water-soluble polymer, as well
• (α7) optionally one or more adjuvants.

When monoethylenically unsaturated, with (α1) copolymerizable monomers, water-soluble polymers and adjuvants In turn, those compounds are preferred which are already mentioned at the beginning in connection with the polymer structures according to the invention as with (α1) copolymerizable Monomers, as water-soluble Polymers or, were called as auxiliary.

Out the aforementioned monomers, comonomers, crosslinkers, water-soluble Polymers and auxiliaries can be the water-absorbing polymer structures produced by various polymerization. For example are in this context Massepolyrnerisation, preferably in kneading reactors such as extruders, solution polymerization, spray polymerization, inverse emulsion polymerization and inverse suspension polymerization to call.

Preferably, the solution polymerization is carried out in water as a solvent. The solution polymerization can be continuous or discontinuous. From the prior art, a wide range of possible variations in terms of reaction conditions such as temperatures, type and amount of initiators and the reaction solution can be found. Typical processes are described in the following patents: US 4,286,082 . DE 27 06 135 . US 4,076,663 . DE 35 03 458 . DE 40 20 780 . DE 42 44 548 . DE 43 23 001 . DE 43 33 056 . DE 44 18 818 , The disclosures are hereby incorporated by reference and thus are considered part of the disclosure.

The Polymerization, as is common practice, by an initiator triggered. As initiators for the initiation of the polymerization, all under the polymerization conditions free-radical initiators used, usually be used in the production of superabsorbents. Also one Initiation of the polymerization by the action of electron beams on the polymerizable, aqueous Mixture is possible. The polymerization can, however, also in the absence of initiators of the type mentioned above by the action of high-energy radiation in the presence of photoinitiators. polymerization can in a solution Inventive monomers solved or dispersed. As initiators come all the person skilled in known compounds decomposing into radicals. This includes in particular those initiators who already in WO 2004/037903 A2 as possible initiators to be named.

Especially is preferred for the preparation of water-absorbing polymer structures a redox system consisting of hydrogen peroxide, sodium peroxodisulfate and ascorbic acid used.

Also the inverse suspension and emulsion polymerization can be used for the preparation be applied to the polymer structure. According to these processes, one becomes aqueous partially neutralized solution the monomers (α1), and (α2), optionally including water-soluble polymers and auxiliaries, with the aid of protective colloids and / or emulsifiers in a hydrophobic, organic solvents dispersed and initiated by radical initiators the polymerization. The crosslinkers are either dissolved in the monomer solution and are combined with it dosed or separately and optionally added during the polymerization. Possibly the addition of a water-soluble Polymers (α4) as a grafting over the monomer solution or by direct submission to the oil phase. Subsequently, will the water is azeotropically removed from the mixture and the polymer filtered off.

Furthermore, in the solution polymerization as well as in the inverse suspension and emulsion polymerization, the crosslinking can be effected by copolymerization of the polyfunctional crosslinker dissolved in the monomer solution and / or by reaction of suitable crosslinkers with functional groups of the polymer during the polymerization steps. The methods are for example in the publications gene US 43 40 706 . DE 37 13 601 . DE 28 40 010 and WO 96/05234 A1, the corresponding disclosure of which is hereby incorporated by reference.

The in the solution polymerization or the inverse suspension and emulsion polymerization in the process step a) hydrogels obtained in process step c) at least partially dried.

Especially in the case of solution polymerization However, it is preferred that the hydrogels before drying in first an additional Process step b) are crushed. This crushing is done by Shredding devices known to the person skilled in the art, such as a Meat grinder.

The Drying of the hydrogel is preferably carried out in suitable dryers or ovens. Exemplary are rotary kilns, Fluid bed dryer, plate dryer, paddle dryer or infrared dryer called. Furthermore, it is preferred according to the invention that the drying of the hydrogel in process step c) to a water content from 0.5 to 50% by weight, preferably from 1 to 25% by weight, especially preferably 2 to 10 wt .-%, wherein the drying temperatures usually in a range of 100 to 200 ° C lie.

The obtained in process step c), at least partially dried water-absorbing polymer structures can, in particular, if they by solution polymerization were obtained in a further process step d) still grind and sieved to the desired grain size mentioned above. The grinding The dried, water-absorbing polymer structure is preferably carried out in suitable mechanical crushers, such as a ball mill.

in the Following the drying of the hydrogels and optionally carried out further preparation of the dried water-absorbing Polymer structures can this in a further process step e) in the surface area modified (except in step e) conducted surface modification is the modification described in more detail below with the compound comprising at least one anion and one polycation and as well as surface postcrosslinking).

As a preferred modification measure here is bringing into contact the outer region of the polymer structures with a compound containing Al ³⁺ ions before, during or after, preferably after, bringing into contact with the postcrosslinker or the fluid containing the postcrosslinker to call. In this case, it is preferable that the compound containing Al ³⁺ ions in an amount in a range of 0.01 to 30 wt .-%, particularly preferably in an amount in a range of 0.1 to 20 wt .-% and moreover, preferably in an amount in a range of 0.3 to 5 wt .-%, in each case based on the weight of the polymer structures, is brought into contact with the polymer structures.

The contacting of the outer region of the polymer structures with the compound containing Al ³⁺ ions is preferably carried out by mixing the polymer structure with the compound under dry conditions or by mixing the polymer structures with a fluid F ₁ comprising a solvent, preferably water water-miscible organic solvents such as methanol or ethanol or mixtures of at least two thereof, as well as the Al ³⁺ ion-containing compound are brought into contact, wherein the contacting is preferably carried out by spraying the polymer particles with the fluid F ₁ and mixing , In this context, it is further preferred that the contacting of the polymer structures with the fluid F ₁ enthal tend the Al ³⁺ ions-containing compound is carried out in a two-stage process. In this case, the two-stage process comprises a first mixing process, in which a plurality of polymer structures is mixed with the fluid F ₁ , and a second mixing process, in which the fluid F _{1 is} homogenized in the interior of the polymer structures, wherein the polymer structures in the first mixing process with a Be mixed speed that the kinetic energy of the individual polymer structures is on average greater than the adhesion energy between the individual polymer structures, and the polymer structures are mixed in the second mixing process at a slower speed than in the first mixing process.

By treating the polymer structures with the fluid F ₁ containing the Al ³⁺ ion-containing compound by the two-step process described above, polymer structures with improved absorption properties can be obtained.

In this case, the Al ³⁺ ion-containing compound is preferably contained in an amount within a range of 0.1 to 50% by weight, more preferably in an amount within a range of 1 to 30% by weight, excluding crystal water based on the total weight of the fluid F ₁ , in the fluid F ₁ included. It is further preferred that the fluid F ₁ in an amount in a range of 0.01 to 15 wt .-%, particularly preferably in an amount in a range of 0.05 to 6 wt .-%, each based on the Weight of the polymer structures, is brought into contact with the polymer structures.

Preferred Al ³⁺ ions are compounds containing AlCl ₃ .6H ₂ 0, NaAl (S0 _{4) 2} × 12 H ₂ O, KA1 (S0 _{4) 2} × 12 H ₂ 0 or Al ₂ (SO _{4) 3} x 14- 18H ₂ O.

When Another surface modification measure was at this point bringing into contact the water-absorbing Polymer structure with inorganic particles, for example with finely divided Silica, which preferably applied in aqueous suspension or with silica sol mentioned.

The modification measures carried out above in process step e), in particular the treatment with a compound containing Al ³⁺ ions, can in principle also be carried out during process steps ii) and iii) or also after carrying out process steps ii) or iii), the use of these Modification measures after carrying out the process steps ii) and iii) is particularly preferred.

Struktur I handelt, in der
R¹ und R² gleich oder verschieden sein können und ein Kohlenwasserstoffrest mit 1 bis 10 Kohlenstoffatomen, vorzugsweise 1 bis 7 Kohlenstoff atomen, besonders bevorzugt 1 bis 4 Kohlenstoffatomen, darüber hinaus bevorzugt 1 bis 2 Kohlenstoffatomen und am meisten bevorzugt eine Methylgruppe darstellen und
n einen Wert von mindestens 25, vorzugsweise mindestens 31, besonders bevorzugt mindestens 100, darüber hinaus bevorzugt mindestens 1.000, darüber hinaus noch mehr bevorzugt mindestens 2.500 und am meisten bevorzugt mindestens 5.000 hat.In process step ii) of the process according to the invention, the untreated, water-absorbing polymer structures are brought into contact with a compound comprising at least one anion and one polycation. In this case, it is preferred according to the invention for the polycation to be a polycation of the structure I

Structure I acts in the
R ¹ and R ^{2 may be the} same or different and are a hydrocarbon radical having 1 to 10 carbon atoms, preferably 1 to 7 carbon atoms, more preferably 1 to 4 carbon atoms, more preferably 1 to 2 carbon atoms, and most preferably a methyl group, and
n has a value of at least 25, preferably at least 31, more preferably at least 100, moreover preferably at least 1,000, moreover still more preferably at least 2,500 and most preferably at least 5,000.

Preferably has the compound containing at least one anion and one polycation a molecular weight of more than 3,000 g / mol, preferably more more than 4,000 g / mol, more preferably more than 5,000 g / mol, moreover even more preferably more than 7,000 g / mol, and most preferably more than 10,000 g / mol.

Especially Preferably, the polycation is a polydiallyldimethylammonium chloride a value for n of at least 25, preferably at least 31, beyond preferably at least 100, even more preferably at least 1,000, more preferably at least 2,500 and most preferably at least 5000.

Furthermore, according to the process of the invention in process step ii) the compound comprising the at least one anion and the polycation directly or by means of another fluid F ₂ comprising a solvent, preferably water, water-miscible organic solvents such as methanol or ethanol or mixtures of at least two of these and this compound are brought into contact with the untreated water-absorbing polymer structure.

Furthermore, it is preferred according to the invention that the untreated water-absorbing polymer structure with this compound in an amount in a range of 0.001 to 10 wt .-%, preferably 0.01 to 7.5 wt .-% and more preferably at least 0.5 to 5 wt .-%, based on the weight of the water-absorbing polymer structure, is brought into contact. Unless this compound is in the form of a fluid F _{2 is} used, it is further preferred that compound in the fluid F ₂ in the form of a 10 to 80 wt .-%, preferably a 20 to 70 wt .-%, most preferably a 30 to 60 wt. % solution, preferably aqueous solution, is brought into contact with the untreated water-absorbing polymer structure.

Suitable mixing units for applying the fluid F ₂ are, in turn, the Patterson-Kelley mixer, DRAIS turbulence mixers, Lödigemischer, Ruberg mixer, screw mixers, plate mixers and fluidized bed mixers and continuously operating vertical mixer, in which the polymer structure is mixed by means of rotating blades in rapid frequency (Schugi mixer).

In process steps iii), if appropriate, the surface postcrosslinking of the water-absorbing polymer structure takes place, in which the polymer structures are first brought into contact and heated with a surface postcrosslinker. In this case, the postcrosslinker, in particular when it is not liquid under the postcrosslinking conditions, is preferably brought into contact in the form of a fluid F ₃ comprising the postcrosslinker and a solvent with the polymer particles. The solvents used are preferably water, water-miscible organic solvents such as methanol, ethanol, 1-propanol, 2-propanol or 1-butanol or mixtures of at least two of these solvents, with water being the most preferred solvent. Furthermore, it is preferred that the postcrosslinker in the fluid F ₃ in an amount in a range of 5 to 75 wt .-%, particularly preferably 10 to 50 wt .-% and most preferably 15 to 40 wt .-%, based on the total weight of the fluid F ₃ , is included.

The bringing into contact of the polymer structure with the fluid F ₃ comprising the postcrosslinker takes place in the process according to the invention preferably by good mixing of the fluid F ₃ with the polymer structure.

Suitable mixing units for applying the fluid F ₃ are in turn z. As the Patterson-Kelley mixer, DRAIS turbulence mixers, Lödigemischer, Ruberg mixer, screw mixers, plate mixers and fluidized bed mixers and continuously operating vertical mixers in which the polymer structure is mixed by means of rotating blades in rapid frequency (Schugi mixer).

The Polymer structure is in the process according to the invention in the post-crosslinking preferably with at most 20 wt .-%, more preferably at most 15 wt .-%, beyond preferably with at most 10% by weight, above even more preferably with at most 5% by weight of solvent, preferably water, brought into contact. and most of all preferred with less than 3 wt .-%, each based on the weight of the polymer structure, brought into contact.

In the case of polymer structures in the form of preferably spherical particles, it is further preferred according to the invention for the contacting to take place so that only the outer area but not the inner area of the particulate polymer structures are brought into contact with the fluid F ₃ and thus with the postcrosslinker.

When Postcrosslinkers which are used in the process according to the invention are preferably understood compounds which are at least two have functional groups with functional groups of a Polymer structure in a condensation reaction (= condensation crosslinker), can react in an addition reaction or in a ring-opening reaction, or but polyvalent metal cations formed by electrostatic interaction between the polyvalent metal cation and the functional groups of a polymer structure enable crosslinking of the polymer structure. As postcrosslinkers, preference is given in the process according to the invention to those in WO 2004/037903 A2 as crosslinkers of crosslinking classes II and IV were called.

Under These compounds are particularly preferred as Nachvernetzer Kondensationsvemetzer such as diethylene glycol, triethylene glycol, polyethylene glycol, Glycerol, polyglycerol, propylene glycol, diethanolamine, triethanolamine, Polyoxypropylene, oxyethylene-oxypropylene block copolymers, sorbitan fatty acid esters, polyoxyethylene, Trimethylolpropane, pentaerythritol, polyvinyl alcohol, sorbitol, 1,3-dioxolan-2-one (Ethylene carbonate), 4-methyl-1,3-dioxolan-2-one (Propylene carbonate), 4,5-dimethyl-1,3-dioxolan-2-one, 4,4-dimethyl-1,3-dioxolan-2-one, 4-ethyl-1,3-dioxolan-2-one, 4-hydroxymethyl-1,3-dioxolan-2-one, 1,3-dioxan-2-one, 4-methyl-1,3-dioxan-2 on, 4,6-dimethyl-1,3-dioxane-on-2 as well as 1,3-dioxolan-2-one.

After the polymer structures have been brought into contact with the postcrosslinker or with the fluid containing the postcrosslinker, they are at a temperature in the range of 50 to 300 ° C, preferably Heated to 75 to 275 ° C and particularly preferably 150 to 250 ° C, so that, preferably, whereby, the outer region of the polymer structures is more crosslinked compared to the interior (= post-crosslinking). The duration of the heat treatment is limited by the risk that the desired property profile of the polymer structures is destroyed as a result of the action of heat.

• 1. Die Verbindung umfassend mindestens ein Anion und ein Polykation bzw. das Fluid F₂ können mit dem im Verfahrensschritt b) erhaltenen Polymergel in Kontakt gebracht werden, welches vorzugsweise noch einen Wassergehalt von mindestens 10 Gew.-%, vorzugsweise mindestens 20 Gew.-% und am meisten bevorzugt mindestens 30 Gew.-% aufweist und erst anschließend erfolgt eines Oberflächennachvernetzung gemäß dem Verfahrensschritt iii).
• 2. Die Verbindung umfassend mindestens ein Anion und ein Polykation bzw. das Fluid F₂ können mit dem im Verfahrensschritt b) gegebenenfalls zerkleinerten Polymergel in Kontakt gebracht werden, wobei auch dieses vorzugsweise noch einen Wassergehalt von mindestens 10 Gew.-%, vorzugsweise mindestens 20 Gew.-% und am meisten bevorzugt mindestens 30 Gew.-% aufweist. Vor, während oder nach dem in Kontakt bringen mit der Verbindung erfolgt die Oberflächennachvernetzung gemäß dem Verfahrensschritt iii).
• 3. Die Verbindung umfassend mindestens ein Anion und ein Polykation bzw. das Fluid F₂ können mit dem im Verfahrensschritt c) erhaltenen getrockneten wasserabsorbierenden Polymergebilden in Kontakt gebracht werden. Vor, während oder nach dem in Kontakt bringen mit der Verbindung erfolgt die Oberflächennachvernetzung gemäß dem Verfahrensschritt iii).
• 4. Die Verbindung umfassend mindestens ein Anion und ein Polykation bzw. das Fluid F₂ können mit dem im Verfahrensschritt d) erhaltenen, zermahlenen wasserabsorbierenden Polymergebilden in Kontakt gebracht werden. Vor, während oder nach dem in Kontakt bringen mit der Verbindung erfolgt die Oberflächennachvernetzung gemäß dem Verfahrensschritt iii).
• 5. Die Verbindung umfassend mindestens ein Anion und ein Polykation bzw. das Fluid F₂ können mit dem im Verfahrensschritt e) erhaltenen, oberflächenmodifizierten wasserabsorbierenden Polymergebilden in Kontakt gebracht werden. Vor, während oder nach dem in Kontakt bringen mit der Verbindung erfolgt die Oberflächennachvernetzung gemäß dem Verfahrensschritt iii).

The bringing into contact of the untreated water-absorbing polymer structures with the compound comprising at least one anion and a polycation or with the fluid F ₂ comprising this compound in process step ii) at different times of the process according to the invention take place:

• 1. The compound comprising at least one anion and a polycation or the fluid F ₂ can be brought into contact with the polymer gel obtained in process step b), which preferably also has a water content of at least 10 wt .-%, preferably at least 20 wt. % and most preferably at least 30 wt .-% and only then followed by a surface postcrosslinking according to the process step iii).
• 2. The compound comprising at least one anion and a polycation or the fluid F ₂ can be brought into contact with the polymer gel optionally comminuted in process step b), whereby this preferably also has a water content of at least 10 wt .-%, preferably at least 20 Wt .-% and most preferably at least 30 wt .-%. Before, during or after bringing into contact with the compound, the surface postcrosslinking is carried out according to process step iii).
• 3. The compound comprising at least one anion and a polycation or the fluid F ₂ can be brought into contact with the dried water-absorbing polymer structures obtained in process step c). Before, during or after bringing into contact with the compound, the surface postcrosslinking is carried out according to process step iii).
• 4. The compound comprising at least one anion and a polycation or the fluid F ₂ can be brought into contact with the ground, water-absorbing polymer structures obtained in process step d). Before, during or after bringing into contact with the compound, the surface postcrosslinking is carried out according to process step iii).
• 5. The compound comprising at least one anion and a polycation or the fluid F ₂ can be brought into contact with the surface-modified water-absorbing polymer structures obtained in process step e). Before, during or after bringing into contact with the compound, the surface postcrosslinking is carried out according to process step iii).

In a particularly preferred embodiment of the method according to the invention, the method steps ii) and iii) are carried out simultaneously. In this case, the compound comprising at least one anion and a polycation or the fluid F _{2 is used} in combination with the F ₃ , wherein a common fluid comprising the compound comprising at least one anion and a polycation and a postcrosslinker can be used. After the polymer structure has been brought into contact with the postcrosslinker and with the compound comprising at least one anion and one polycation at the same time in process steps ii) and iii), the postcrosslinking is carried out by heating the polymer structures to the above mentioned postcrosslinking temperatures.

Each of these variants 1 to 5 represents a particular embodiment of the method according to the invention, variant 4 being the most preferred. In this case, it is further preferred that in the variant 4, following the surface postcrosslinking, a modification by means of a compound containing Al ³⁺ ions is carried out according to the process step e) described above.

a further contribution to the solution The objects described in the introduction provide the method according to the invention available, surface-treated water-absorbing polymer structures.

there it is preferred that the water-absorbing described above Polymer structures have the same properties as through the method according to the invention available surface-treated water-absorbing polymer structures. It is also preferred according to the invention that those values associated with the method of the invention and the polymer structures according to the invention as lower limits of features according to the invention without upper limits 20 times, preferably 10 times and especially preferably 5 times the most preferred value of the lower limit have.

A further solution to the problems described at the outset is provided by a composite comprising the surface-treated water-absorbing polymer structures according to the invention or the surface-treated water-absorbing polymer structures obtainable by the process according to the invention and a substrate. It is preferred that the polymer structures of the invention and the substrate with each other are firmly connected. As substrates, films of polymers, such as of polyethylene, polypropylene or polyamide, metals, nonwovens, fluff, tissues, fabrics, natural or synthetic fibers, or other foams are preferred. Furthermore, it is preferred according to the invention that the composite comprises at least one region which contains the water-absorbing polymer structure according to the invention in an amount in the range from about 15 to 100% by weight, preferably about 30 to 100% by weight, particularly preferably from about 50 to 99.99 wt .-%, further preferably from about 60 to 99.99 wt .-% and more preferably from about 70 to 99 wt .-%, each based on the total weight of the respective region of the composite includes, said Range preferably has a size of at least 0.01 cm ³ , preferably at least 0.1 cm ³ and most preferably at least 0.5 cm ³ .

In a particularly preferred embodiment of the composite according to the invention it is a sheet-like composite, as described in WO-A-02/056812 as "absorbent material " is. The disclosure of WO-A-02/056812, in particular with regard to the exact structure of the composite, the basis weight of its components and its thickness is hereby introduced as a reference and provides a part of the disclosure of the present invention.

a further contribution to the solution The tasks mentioned at the beginning provide a method of manufacture a composite, wherein the water-absorbing polymer structures according to the invention or by the method according to the invention available surface-treated water-absorbing polymer structures and a substrate and optionally an additive are brought into contact with each other. As substrates For example, those substrates which are already used are preferably used have been mentioned above in connection with the composite according to the invention.

a Contribution to the solution The input mentioned tasks also provides a bond available after the method described above, this composite preferably has the same properties as the one described above, composite according to the invention.

a further contribution to the solution The tasks mentioned at the beginning provide chemical products the water-absorbing invention Polymer structure or a composite according to the invention. Preferred chemical Products are especially foams, Moldings, Fibers, films, films, cables, sealing materials, liquid-absorbent Hygienic articles, in particular diapers and sanitary napkins, carriers for plant or fungi growth regulators or crop protection agents, additions for building materials, Packaging materials or floor additives.

Also the use of the water-absorbing invention Polymer structure or the composite according to the invention in chemical Products, preferably in the aforesaid chemical products, especially in hygiene articles such as diapers or sanitary napkins, as well the use of the superabsorbent particles as a carrier for plant or fungi growth-regulating Agents or crop protection agents contribute to the solution of initially mentioned tasks. When used as a carrier for plant growth or fungi growth regulating agents or crop protection agents it is preferred that the plant or fungi growth regulating Agents or crop protection agents are controlled by the carrier Period can be submitted.

Struktur I in der
R¹ und R² gleich oder verschieden sein können und ein Kohlenwasserstoffrest mit 1 bis 10 Kohlenstoffatomen, vorzugsweise 1 bis 7 Kohlenstoffatomen, besonders bevorzugt 1 bis 4 Kohlenstoffatomen, darüber hinaus bevorzugt 1 bis 2 Kohlenstoffatomen und am meisten bevorzugt eine Methylgruppe darstellen und
n einen Wert von mindestens 25, vorzugsweise mindestens 31, besonders bevorzugt mindestens 100, noch mehr bevorzugt mindestens 1.000, darüber hinaus bevorzugt mindestens 2.500 und am meisten bevorzugt mindestens 5.000 hat,

• – zur Behandlung der Oberfläche wasserabsorbierender Polymergebilde, und/oder
• – zur Verbesserung der Permeabilität von Verbunden umfassend diese Polymergebilde und ein Substrat, wobei die Polymergebilde in dem Verbund in einer Menge von mindestens 50 Gew.-%, vorzugsweise mindestens 70 Gew.-% und am meisten bevorzugt mindestens 90 Gew.-%, bezogen auf das Gesamtgewicht aus Polymergebilde und Substrat, in dem Verbund enthalten sind.

A further contribution to the solution of the abovementioned object is provided by the use of a compound comprising at least one anion and one polycation of structure I.

Structure I in the
R ¹ and R ^{2 may be the} same or different and represent a hydrocarbon radical having 1 to 10 carbon atoms, preferably 1 to 7 carbon atoms, more preferably 1 to 4 carbon atoms, more preferably 1 to 2 carbon atoms, and most preferably a methyl group, and
n has a value of at least 25, preferably at least 31, more preferably at least 100, even more preferably at least 1,000, moreover preferably at least 2,500 and most preferably at least 5,000,

• For the treatment of the surface of water-absorbing polymer structures, and / or
• - to improve the permeability of composites comprising these polymer structures and a substrate, wherein the polymer structures in the composite in an amount of at least 50 wt .-%, preferably at least 70 wt .-% and most preferably at least 90 wt .-%, based on the total weight of polymer structure and substrate, are included in the composite.

The Invention will now be based on test methods and not limiting Examples closer explained.

TEST METHODS

DETERMINATION OF PERMEABILITY (SFC TEST, According to WO-A-95/22356)

wobei:

F_s(t=0)

die Fliessrate in g/s,

L₀

die Dicke der Gelschicht in cm,

r

die Dichte der NaCl-Lösung (1,003 g/cm³),

A

die Fläche der Oberseite der Gelschicht im Messzylinder (28,27 cm²),

ΔP

der hydrostatische Druck, der auf der Gelschicht lastet (4920 dyne/cm²), und

K

der SFC-Wert ist [cm³·s – g^–1]

0.9 g of superabsorbent material are weighed into a cylinder with sieve bottom and carefully distributed on the sieve surface. The superabsorbent material is dissolved in JAYCO synthetic urine (composition: 2.0 g of potassium chloride, 2.0 g of sodium sulfate, 0.85 g of ammonium dihydrogen phosphate, 0.15 g of ammonium hydrogen phosphate, 0.19 g of calcium chloride, 0.23 g of magnesium chloride as anhydrous salts in 1 I distilled water) for 1 hour against a pressure of 20g / cm ² swell. After detecting the swelling height of the superabsorber, at a constant hydrostatic pressure, 0.118 M NaCl solution from a leveled storage vessel is passed through the swollen gel layer. The swollen gel layer is covered during the measurement with a special screen cylinder, which ensures a uniform distribution of the 0.118 M NaCl solution above the gel and constant conditions (measuring temperature 20-25 ° C) during the measurement with respect to the gel bed condition. The pressure acting on the swollen superabsorber is still 20 g / cm ² . With the aid of a computer and a balance, the amount of fluid that passes through the gel layer as a function of time is recorded at 20-second intervals within a 10-minute period. The flow rate in g / s through the swollen gel layer is determined by regression analysis with extrapolation of the slope and determination of the center point to the time t = 0 of the flow rate within minutes 2-10. The SFC value (K) is calculated as follows

in which:

F _s (t = 0)

the flow rate in g / s,

L ₀

the thickness of the gel layer in cm,

r

the density of the NaCl solution (1.003 g / cm ³ ),

A

the area of the top of the gel layer in the measuring cylinder (28.27 cm ² ),

.DELTA.P

the hydrostatic pressure, which rests on the gel layer (4920 dyne / cm ² ), and

K

the SFC value is [cm ³ · s - g ^-1 ]

DETERMINATION OF THE WICKING INDEX

The Determination of the wicking index was carried out in accordance with that on page 6, line 36 to page 7, line 26 of EP-A-0 532 002, wherein the particles previously have a particle size in a range of 150 up to 850 μm were screened.

1. PREPARATION OF SAP PARTICLES (NEUTRALIZATION RATE 5O MOL-%)

A monomer solution consisting of 300 g of acrylic acid, 166.52 g of 50% sodium hydroxide solution, 497.12 g of deionized water, 1.176 g of monoallyl polyethylene glycol 450 monoacrylic acid ester, 0.988 g of polyethylene glycol 300 diacrylate and 6.13 g of polyethylene glycol 750 monomethyacrylsäureestermethylether freed from the dissolved oxygen by purging with nitrogen and cooled to the starting temperature of 4 ° C. After reaching the starting temperature, the initiator solution (0.3 g of sodium peroxydisulfate in 9.7 g of H ₂ O, 0.07 g of 35.5% hydrogen peroxide solution in 1.93 g of H ₂ 0 and 0.015 g of ascorbic acid in 4.99 g H ₂ 0) was added. After the final temperature of about 100 ° C was reached, the resulting gel was crushed and at 150 ° C for 120 minutes dried. The dried polymer was crushed roughly, ground and sieved to a powder with a particle size of 150 to 850 microns (= powder A).

2. PREPARATION OF SAP PARTICLES (NEUTRALIZATION GRADE 70 MOL-%)

A monomer solution consisting of 300 g of acrylic acid, 233.12 g of 50% sodium hydroxide, 429.42 g of deionized water, 1.961 g Monoallylpolyethylenglykol-450 monoacrylic acid ester, 2.372 g of polyethylene glycol 300 diacrylate and 6.13 g of polyethylene glycol 750 monomethyacrylsäureestermethylether freed from the dissolved oxygen by purging with nitrogen and cooled to the starting temperature of 4 ° C. After reaching the starting temperature, the initiator solution (0.3 g of sodium peroxydisulfate in 9.7 g of H ₂ O, 0.07 g of 35.5% hydrogen peroxide solution in 1.93 g of H ₂ 0 and 0.015 g of ascorbic acid in 4.99 g H ₂ 0) was added. After the final temperature of about 100 ° C was reached, the resulting gel was crushed and dried at 150 ° C for 120 minutes. The dried polymer was roughly crushed, ground and sieved to a powder having a particle size of 150 to 850 μm (= Powder B).

Examples 1 and 2 (SAP polymer with a degree of neutralization of 70 mol%) Powder B was treated with a solution comprising the amounts of water, ethylene carbonate as postcrosslinker and polydiallyldimethylammonium chloride (MW = 450,000 g / mol) given in Table 1 below with vigorous stirring and then heated for the duration indicated in Table 1 to the temperatures also indicated in Table 1 (the amounts of water, ethylene carbonate and polydiallyldimethylammonium chloride are in each case the amounts in grams, based on 100 g of the powder B): Table 1

The absorption properties of the polymers obtained in Examples 1 to 4 are listed in the following Table 2: TABLE 2

Examples 3 and 4 (SAP polymer with 50 mol% neutralization degree)

The powder A was mixed with a solution containing the amounts of water, ethylene carbonate as postcrosslinker and polydiallyldimethylammonium chloride (MW = 450,000 g / mol) given in Table 3 below with vigorous stirring and then for the duration indicated in Table 3 on the also in temperatures indicated in Table 3 (the amounts of water, ethylene carbonate and polydiallyldimethylammonium chloride stated are in each case the amounts in grams, based on 100 g of the powder A): Table 3

The absorption properties of the polymers obtained in Examples 1 to 4 are listed in Table 4 below: TABLE 4

Claims (22)

A water-absorbing polymer structure whose surface has been contacted with a compound comprising a polycation and at least one anion and which preferably has an absorption under a pressure of 50 g / cm ² of at least 16 g / g. Water-absorbing polymer structure whose surface with a compound comprising a polycation and at least one anion has been brought into contact, wherein the compound comprising a Polycation and at least one anion a weight average molecular weight of more than 3,000 g / mol. Water-absorbing polymer structure according to claim 1 or 2, comprising an interior and an interior surrounding outdoor area, the outdoor area has a higher degree of crosslinking has as the interior area. A water-absorbing polymer structure according to any one of the preceding claims, wherein the polycation has the structure I

Structure I, in which R ¹ and R ^{2 may be the} same or different and represent a hydrocarbon radical having 1 to 10 carbon atoms and n has a value of at least 25. A polymer structure according to claim 4, wherein R ¹ and R ^{2 represent} a methyl group. Polymeric structure according to claim 4 or 5, wherein n is a Value of at least 1,000. Polymeric structure according to claim 4 or 5, wherein n is a Value of at least 2,000. Polymeric structure according to claim 4 or 5, wherein n is a Value of at least 3,000. Polymeric structure according to one of the preceding claims, wherein the anion is a chloride ion. Polymeric structure according to one of the preceding claims, wherein the polymer structure has at least one of the following properties: (β1) no caking after three hours; (β2) at an CRC value of less than 26 g / g, an SFC value (of at least 80 × 10 ^-7 cm ³ sg ^-1 ; (β3) at a CRC value in the range of 26 to <27 g / g an SFC value of at least 70 x 10 ^-7 cm ³ sg ^-1 ; (β4) at a CRC value in the range of 27 to <28 g / g an SFC value of at least 60 x 10 ^-7 cm ³ sg ^-1 (β5) at a CRC value in the range of 28 to <29 g / g, an SFC value of at least 45 x 10 ^-7 cm ³ sg ^-1 ; (β6) with a CRC value in the range of 29 to <30 g / g, an SFC value of at least 30 × 10 ^-7 cm ³ sg ^-1 ; (β7), at a CRC value in the range of 30 to <31 g / g, an SFC value of at least 20 × 10 ^-7 cm ³ sg ^-1 ; (β8) at a CRC value of at least 31 g / g an SFC value of at least 10 × 10 ^-7 cm ³ sg ^-1 ; (β9) a wicking index after one minute of at least 7.5 cm; (β10) a degree of neutralization of at most 75 mol%. A method of treating the surface of water-absorbent Polymer structure comprising the method steps: i) Provide an untreated, water-absorbing polymer structure, ii) bringing the untreated water-absorbing polymer structure into contact comprising at least one anion and one polycation Connection, iii) post-crosslinking of the water-absorbing polymer structure, in which the method step iii) before, during or after the method step ii) can be. The method of claim 11, wherein the polycation has the structure I

Structure I has, in which R ¹ and R ^{2 may be the} same or different and represents a hydrocarbon radical having 1 to 10 carbon atoms and n has a value of at least 25. The method of claim 11 or 12, wherein the water-absorbing Polymer structure with the compound in an amount in one area from 0.001 to 10% by weight, based on the weight of the water-absorbing Polymergebildes, is brought into contact. Method according to one of the preceding claims, wherein the compound in the form of a 10 to 80 wt .-% aqueous solution brought into contact with the water-absorbing polymer structure becomes. Method according to one of the preceding claims, wherein the water-absorbing polymer forms a degree of neutralization of not more than 70 mol%. Water-absorbing polymer structure, obtainable according to a method according to any one of the preceding claims. Composite containing a water-absorbing polymer structure according to one of the claims 1 to 10 or 16 and a substrate. Process for the preparation of a composite, wherein a water-absorbing polymer structure according to one of claims 1 to 10 or 16 and a substrate and optionally an adjuvant with each other be brought into contact. Composite, available according to a method according to claim 18th mousses, Moldings, Fibers, films, films, cables, sealing materials, liquid-absorbent hygiene articles, carrier for plant and fungal growth regulating agents, packaging materials, bottom additives or Building materials include the water-absorbing polymer structure one of the claims 1 to 10 or 16 or the composite according to claim 17 or 19. Use of the water-absorbing polymer structure according to one of the claims 1 to 10 or 16 or the composite according to claim 17 or 19 in foams, moldings, fibers, Films, films, cables, sealing materials, liquid-absorbent hygiene articles, carriers for plant and fungal growth regulating agents, packaging materials, soil additives, for controlled release of active substances or in building materials. Use of a compound comprising at least one anion and a polycation of structure I.

Structure I in which R ¹ and R ^{2 may be} identical or different and represent a hydrocarbon radical having 1 to 10 carbon atoms and n has a value of at least 25, for the treatment of the surface of water-absorbing, preferably post-crosslinked polymer structures.